JPH1112231A - Method for producing diamine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a diamine by distilling a crude reaction solution containing a diamine obtained by performing a reductive amination reaction using a dialdehyde as a raw material, to solidify a liquid at a lower portion of a distillation column and to reduce the solidification thereof. Problems associated with a low yield, such as a decrease in the diamine recovery rate, are solved. SOLUTION: To a crude reaction liquid containing a diamine obtained by performing a reductive amination reaction, a primary monoamine and / or hydroxylamine which can be separated from the diamine by distillation are distilled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to various polyamides,
The present invention relates to a method for producing an industrially useful diamine as a raw material of polyurethane.

[0002]

2. Description of the Related Art A method for producing a diamine by reductive amination using a dialdehyde as a starting material in the presence of a hydrogenation catalyst, hydrogen and ammonia is disclosed, for example, in JP-A-5-17413.
It is publicly known from Japanese Patent Publication No. This publication discloses that a crude reaction solution containing a diamine obtained by the reaction can be easily purified to a high purity by a general isolation and purification method, for example, by removing the catalyst from the reaction solution by filtration and then purifying by distillation. It is described that a diamine can be obtained.

[0003]

However, the present inventors have further tried the diamine production method disclosed in the above publication, and found that the diamine obtained according to the above production method is purified by distillation from a crude reaction solution. Has a major problem. In other words, a phenomenon was observed in which a gel-like solid was formed at the bottom of the distillation apparatus during the distillation, and the distillation could not be continued. Such solidification is particularly remarkable when distilling a crude reaction solution having a low diamine yield in the reductive amination reaction. When this gel-like solidified product is produced, there is a problem that the distillation cannot be continued and the target diamine is taken into the solidified product, so that the diamine recovery rate from the crude reaction solution is reduced.

Accordingly, it is an object of the present invention to provide a method for distilling a crude diamine reaction solution obtained by performing a reductive amination reaction using dialdehyde as a starting material to form a gel-like solidified substance at a lower portion of a distillation apparatus, and To prevent that the continuation of can not be performed, and also prevent the target diamine is taken into the solidified product and the recovery rate of the diamine is reduced,
An object of the present invention is to provide an industrially advantageous method for producing a diamine.

[0005]

According to the present invention, an object of the present invention is to provide a diamine obtained by performing a reductive amination reaction using a dialdehyde as a starting material in the presence of a hydrogenation catalyst, hydrogen and ammonia. Is obtained by adding a primary monoamine and / or hydroxylamine capable of being separated from the diamine by distillation to a crude reaction solution containing the diamine, followed by distillation.

The inventor of the present invention has used various analytical methods to find that a crude reaction solution after reductive amination contains a complex of an amine and an aldehyde having a Schiff base bond formed by the reaction of an amino group and an aldehyde group. Admitted that. By heating this crude reaction solution in the distillation step, it was found that the Schiff base bonding portion caused aldol condensation and generated high-boiling impurities. Then, as a result of further intensive studies, the production of this high-boiling-point impurity was suppressed by providing a method for producing a diamine according to the present invention, and the above object was achieved.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the dialdehyde used as a starting material for diamine synthesis has 4 to 20 carbon atoms.
More preferred are dialdehydes having a straight-chain aliphatic, branched-chain aliphatic, alicyclic or aromatic skeleton having 8 to 12 carbon atoms. Specifically, linear aliphatic dialdehydes such as butanedial, hexanedial, octanedial, nonandial, decandial, dodecandal, hexadecandial, octadecandial, eicosandial, and the like; 2-methyloctanedial , 2
Branched aliphatic dialdehydes such as -methyl-nonandial, 2,7-dimethyloctanedial; 1,3- or 1,4-cyclohexanedicarbaldehyde;
Alicyclics such as (4), 8 (9) -tricyclo [5.2.1.0] decandicarbaldehyde, 2 (3), 5 (6) -bicyclo [2.2.1] heptanedicarbaldehyde Examples are formula dialdehydes; or aromatic dialdehydes such as terephthalaldehyde, isophthalaldehyde.

Using the above dialdehydes as raw materials, linear aliphatic diamines such as butanediamine, hexanediamine, octanediamine, nonanediamine, decanediamine, dodecanediamine, hexadecanediamine, octadecanediamine and eicosanediamine;
Branched aliphatic diamines such as -methyloctanediamine, 2-methyl-nonanediamine, and 2,7-dimethyloctanediamine; 1,3- or 1,4-cyclohexanedimetamine, 3 (4), 8 (9)- Tricyclo [5.2.1.0] decandimethanamine, 2 (3), 5
Alicyclic diamines such as (6) -bicyclo [2.2.1] heptanedimethanamine; or p-xylenediamine;
Aromatic diamines such as m-xylene diamine are produced.

The hydrogenation catalyst used for the reductive amination of the diamine synthesis in the present invention includes Raney catalysts such as Raney nickel, Raney cobalt and Raney copper, and hydrogenation catalysts such as nickel, cobalt, platinum, palladium, rhodium, ruthenium and copper. Diatomaceous earth, silica,
A supported catalyst supported on a carrier such as alumina, silica alumina, clay, titania, zirconia, magnesia, calcia, lanthanum oxide, niobium oxide, carbon, or a metal and organic such as nickel, cobalt, platinum, palladium, rhodium, ruthenium, copper, etc. Alternatively, a metal complex catalyst comprising an inorganic ligand can be used.

In the reductive amination reaction for synthesizing the diamine, the conditions such as temperature, hydrogen pressure, amount of ammonia used, solvent, reaction method and reaction apparatus are not particularly limited, and the reaction is carried out by a known method.

The primary monoamine used in the present invention has a higher boiling point than the target diamine, and the target diamine is distilled first on the low boiling point side during distillation, so that it can be easily separated from the diamine. Primary monoamines having an aromatic skeleton are preferred. Specifically, octylamine,
Decylamine, dodecylamine, hexadecylamine,
Octadecylamine, 2-methyloctylamine, 2-
Aliphatic amines such as methyl dodecylamine and 2,2-dimethyloctylamine; 2-aminomethylnaphthalene;
Examples thereof include aromatic amines such as 2-aminomethylanthracene and 2-aminomethylphenanthrene. Among them, those having a higher boiling point than the desired diamine are used. For example, when the target diamine is 1,9-nonanediamine or 2-methyl-1,8-octanediamine, it is appropriate to use hexadecylamine, octadecylamine, or the like. As hydroxylamine, commercially available hydroxylamine or an aqueous hydroxylamine solution is used.

The amount of the primary monoamine and / or hydroxylamine to be used can be determined in accordance with the quantitative analysis of the amount of the Schiff base present in the target amination crude reaction solution and the analysis value. The range of use is preferably 0.5 to 10 times the molar amount of the number of moles of the Schiff base bond,
A 5-fold molar amount is more preferred.

The primary monoamine or hydroxylamine added here exchanges with the amino group of the diamine which is involved in the formation of a complex between the amine having a Schiff base bond and the aldehyde, and the complex has an amino group at both ends. Changes to a structure without groups. Therefore, even if the Schiff base portion causes aldol condensation by heating, generation of a high-boiling solid which is a problem during distillation is suppressed.

The time for adding the primary monoamine is as follows.
In a diamine distillation step, before the crude reaction solution is heated and a high-boiling substance is generated by the aldol condensation of the Schiff base, before the solvent recovery distillation or before the rectification of the crude diamine solution after solvent removal. But it is good. Also, it may be added during the preparation of the reductive amination reaction or during the reaction.

Similarly, when the hydroxylamine is added at a stage before the crude reaction solution is heated in the diamine distillation step and a high-boiling product is formed by the aldol condensation of the Schiff base, the solvent recovery distillation is performed. Before the rectification, or before the rectification of the crude diamine solution after the solvent is removed. When hydroxylamine is added, for example, the crude reaction solution to which hydroxylamine is added before distillation is stirred at room temperature for about several minutes to several hours, and the amino group of the diamine forming a multimer having a Schiff base bond is added. It is preferable to previously carry out an exchange reaction between OH and an amino group of hydroxylamine.

A series of operations in the distillation step do not require special consideration for temperature, pressure, etc., and are carried out according to a known method. Since the added primary monoamine has a higher boiling point than the target diamine, it can be easily separated by distillation as a high-boiling fraction. Of the added hydroxylamines, those that have reacted with the Schiff base moiety are high-boiling fractions, and those that have not reacted are low-boiling fractions, and can be easily separated by distillation from the target diamine.

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 First, a stirred autoclave charged with 15 g of a Raney nickel catalyst as a hydrogenation catalyst, 150 g of a methanol solvent, and 111 g of ammonia was charged at 120 ° C. and a hydrogen pressure of 40 kg / c according to a known method (Japanese Patent Laid-Open No. 5-17413).
After a m ^2, 1,9-Nonanjiaru and 2 A mixture 78.4g of methyl-1,8-di Earl over 3 hours a raw material solution obtained by dissolving in methanol solvent 160g was fed into the autoclave, 1 390 g of a crude reaction solution containing 2,9-nonanediamine and 2-methyl-1,8-octanediamine was obtained. At this time, the yield of 1,9-nonanediamine and 2-methyl-1,8-octanediamine was 36.9% based on 1,9-nonandial and 2-methyl-1,8-octanedial.
The content of 1,9-nonanediamine and 2-methyl-1,8-octanediamine in the crude reaction solution was 29.3 g.
(7.5 wt%), the amount of Schiff base bonds was 1 g of crude reaction solution.
0.54 mmol / mol. Next, this crude reaction solution was charged into a simple distillation apparatus, and 50.8 g of hexadecylamine in an equimolar amount to the Schiff base bond was added. After gradually changing the temperature and the degree of decompression in the lower part of the distillation apparatus (hereinafter sometimes referred to as the bottom) and distilling off the methanol solvent and a small amount of low-boiling by-products, the bottom temperature was 180 ° C. and the depressurization degree was 1
Distillation was carried out at 0 torr for 1 hour to distill 1,9-nonanediamine and 2-methyl-1,8-octanediamine. At this time, the amount of 1,9-nonanediamine and 2-methyl-1,8-octanediamine recovered as fractions was 30.5 g (distillation recovery rate: 104.1%). At this time, no solidification of the bottom liquid was observed, and a smooth distillation operation could be continued. 1,9-nonanediamine and 2-methyl-1,1, which could be recovered as fractions by distillation
The amount of 8-octanediamine is determined by the amount of 1,9-nonanediamine and 2-methyl-
The reason for exceeding the amount of 1,8-octanediamine is presumably because the added hexadecylamine exchanged with the amino group of the diamine forming a Schiff base bond, and the diamine was regenerated.

Example 2 First, 390 g of a crude reaction solution containing 1,9-nonanediamine and 2-methyl-1,8-octanediamine obtained in the same manner as in Example 1 was charged into a simple distillation apparatus and subjected to Schiff base binding. Then, 35 g of a 50% aqueous solution of hydroxylamine, which was 2.5 mole times the amount of the above, was added, and then stirred at room temperature for 30 minutes. Next, the bottom temperature and the degree of reduced pressure were gradually changed, and a methanol solvent, a small amount of low-boiling by-products, and unreacted hydroxylamine were distilled off.
Distillation was performed at a reduced pressure of 10 torr for 1 hour to distill 1,9-nonanediamine and 2-methyl-1,8-octanediamine. At this time, 1,9
The amount of -nonanediamine and 2-methyl-1,8-octanediamine was 29.8 g (distillation recovery rate: 101.7%). In addition, no solidification of the bottom liquid was observed by distillation, and a smooth distillation operation could be continued.

Example 3 In the reductive amination reaction of Example 1, 1,9-nonanediamine and 2-methyl-1,2-methyl-1,2-methyl-1,2-methyl-1,2 390 g of a crude reaction solution containing 8-octanediamine was obtained. At this time, the yield of 1,9-nonanediamine and 2-methyl-1,8-octanediamine based on 1,9-nonandial and 2-methyl-1,8-octanedial was 80.0%. The content of 1,9-nonanediamine and 2-methyl-1,8-octanediamine in the crude reaction solution was 62.7 g (16.1 wt%),
The amount of Schiff base bonds was 0.12 mmol / g of crude reaction solution. Next, this crude reaction solution was charged into a simple distillation apparatus, and octadecylamine 1 in an equimolar amount to the Schiff base bond was used.
2.5 g were added. After gradually changing the bottom temperature and the degree of reduced pressure to distill off the methanol solvent and a small amount of low-boiling by-products, distillation was performed for 1 hour at a bottom temperature of 190 ° C. and a degree of reduced pressure of 10 torr, and 1,9-nonanediamine and 2-methyl -1,8-octanediamine was distilled off. At this time, 1,9-nonanediamine and 2-
The amount of methyl-1,8-octanediamine was 58.8 g (distillation recovery rate: 93.9%). In addition, no solidification of the bottom liquid was observed by distillation, and a smooth distillation operation could be continued.

Comparative Example 1 1,9-Nonanediamine and 2-methyl-1,8-octanediamine 29.3 obtained in the same manner as in Example 1.
Using 390 g of a crude reaction solution containing g, no hexadecylamine was added, the distillation bottom temperature was set to a maximum of 140 ° C., and the degree of reduced pressure was set to 1 torr. . At this time, when the distillation was performed at a bottom temperature of 140 ° C. for 30 minutes, the bottom liquid was solidified and the distillation operation became impossible. The 1,9-nonanediamine and 2-methyl-
21.7 g of 1,8-octanediamine (distillation recovery rate 7
4.1%).

Comparative Example 2 1,9-Nonanediamine and 2-methyl-1,8-octanediamine 62.7 obtained in the same manner as in Example 3.
Using 390 g of the crude reaction solution containing g, diamine was recovered and distilled in the same manner as in Example 1 except that octadecylamine was not added. At this time, the bottom temperature 190
At the time when the distillation was performed at 1 ° C. for 1 hour, the bottom liquid was solidified and the distillation operation became impossible. 1,9-nonanediamine and 2-methyl-1,8-
55.8 g of octanediamine (distillation recovery rate: 89.0 g)
%)Met.

[0022]

According to the present invention, a diamine is obtained by distilling a crude reaction solution containing a diamine obtained by performing a reductive amination reaction using a dialdehyde as a raw material.
Problems such as solidification of the liquid at the bottom of the distillation column and the accompanying decrease in the diamine recovery rate can be overcome.

Claims (2)

[Claims] 1. A diamine-distillable diamine is used as a starting material in a crude reaction solution containing a diamine obtained by performing a reductive amination reaction in the presence of a hydrogenation catalyst, hydrogen and ammonia. A process for producing a diamine, comprising adding a primary monoamine and / or hydroxylamine and performing distillation. 2. The diamine is 1,9-nonanediamine,
The method for producing a diamine according to claim 1, which is 2-methyl-1,8-octanediamine or a mixture thereof.